Electric switch



.Emme 29, H943. Q RCHARDSON ET AL 2,323,241

ELECTRIC SWITCH Filed Oct. 25, 1940 2 Sheets-Sheet l INVEN ORS `Iune 29, 1943. o. RICHARDSON ET AL 2,323,241

ELECTRIC SWITCH Filed Oct. 25. 1940 2 Sheets-Sheetl 2 I' hasta! .masas-,194s f UNl'rEDsTATE-s, luiriarslr OFFICE l 4' f A 2,323,241

mc'rnxcswrron oumlueanann, um. au .mm a. caidwelland William AGM'. Birming All.,

Anuman ommen, im, sensi No. uam

(ci. zoo-4s) 13 Claims.

One purpose oi the invention is to provide a high voltage air-brake switch that can be opened under heavy load without causing serious arcing; another purpose is to provide a switch that can be opened and reclosed often with a minimum of deterioration: another purpose is to provide a switch which has also the arc-suppressing qualities of the well-known expulsion-tube fuse; and other purposes will be evident from the specincation and claims.

In the drawings, Fig. 1 shows a side elevation of a single switch unit embodying the invention; Fig. 2 is a top view in partial section of the same unit in closed position with the cover removed; Fig. 3 is similar to Fig. 2 but with the switch open; Fig. 4 shows in section the switch jaws and contact members; and Figs. 5 and 6 show details of the jaws when the switch is closed; Figs. 7 and 8 show in larger scale some details of the latch and release members, Fig. 8 being a view of Fig. 7 from position AA.

The base I carries two stationary insulator units 2, 3 and one movable insulator unit 4 which is rotatable in its supporting bearing 5 by means oi the crank 6. Another crank 'I and the pipe and clevis l serve to connect this unit to other similar units to form a 3-pole switch in the well known manner. The switch arm is pivoted to swing about the stationary stud 9 and it includes the box member I0, the insulating tubular member II and the contact tip I2, whereby contact is made with the stationary jaw members I3, I4 which are supported upon the insulator 2. The tubeV II preferably has a horn fibre lining II1 to increase the arc-suppressing eilect. Line connections are made at I5 and I6.

The stud 9 is rigid with the top-casting I1 which also has an arm which carries the bearing I8 wherein is the stud I9 held by the pin 29 and acting as a top bearing for the rotatable insulator 4. Fixed to the insulator 4 is the crank 2i to which is attached the connecting link 22 by means of the pivot 23. The other end of the link 22 is rigidly attached to the shaft 24, and the operating arm 25 is rigidly secured to the .other end of shaft 24., 'I'he biased arm 26 pivots about the shaft 24 and it is biased towards the open switch position by the spring 2l. All movable joints have easy clearances suitable for operation under outdoor conditions.

'I'he latch 28 is pivoted to the operating arm 25 and engages with the projection 29 on the biased arm 2E; its motion is controlled by a spring 44 and stop 28'. 'Ihe parts are so proportioned that when the arm 26 is already in fully open position and arm 29 is then moved into its fully open position, the latch 2l re-engages with projection 2i. The ratchet 3l is pivoted to the box il. It is controlled by a suitable spring 4I and stop Il' and it engages with a projection on 2l when the switch is in closed position. The biased arm 2l is pivotally connected by the link 3i with the slide 32 and the rod 33. The stationary rod 34 serves as a guide for the slide 22 and for the rod which is secured to I2. The other end ofthe rod Il has a tapered end Il, preferably oi' heat resisting mtal with a carbon arcing tip Il'. When being lclosed the tapered tip enters between the buttons 96, 3l which are mounted upon the springs 3l, 39 and it forcibly spreads the buttons outwardly against the heavy spring jaws Il, I4 thereby obtaining good conductivity at all contact points. The rod I3 preferably has a rather close t finside the tube II in order to minimize the escape of gases towards Il.

Stops 4I, 42, and '49 prevent overtravel of the various members, and stop 4I is so arranged that it provides a cushion to soften the hammer-blow of the rod 33 as it completes its rapid opening movement. Suitable flexible conductors, not shown, are used as iumpers to shunt the various joints in the conducting paths.

Operation is as follows: With the switch closed as shown in Fig. 2, the line AA is drawn through the center of the pivot 24v and the center of the rotative insulator 4. The first opening motion of the crank 2I brings the pivot 23 closer to the line AA and so the link 22 rotates the shaft 24, to which it is rigidly attached, without materially moving the shaft 24 from its location. After the pivot 23 has first crossed the line AA it continues to rotate the pivot 24 without materially changing its location. Thus during the beginning of the opening stroke, the operating arm 25, and so the rod u, make a substantial travel towards their open positions before the main switch arm Il, II, I2 has moved the contacts 36, Il free from the Jaw members I3, I4. Further rotation of insulator 4 brings the arm I9, II, I2 to the fully open position shown in Fig. 3.

Atk the beginning of the opening stroke, the ratchet Il holds the projection on the latch 28, and-so the first opening motion of the link 22 swings-the operating arm 2S and so rotates the latch 2l thereby disengaging 29 from the projection 29 on the biased arm 2l. Thereupon the spring 2l immediately snaps the biased arm- 26 to its fully open position, and this also instantly moves the rod I3 to its fully open position. This draws the arc down into the tube II, quenching in the well known manner. The ratchet 2l does not hold the latch 2l when 2l has been partly rotated, and so continued motion ot the crank 2l moves the shaft 2l, and with it the switch arm Il, Il, i2 to the fully open position shown in F18. 3. This brings the latch 2i into position where it re-engages with the projection Il.

The motion of the crank 2l from :fully open position towards the closed position swings the switch arm I0, Il, I2 towards closed position and also rotates the arms and 28 together towards their closed position. The switch arm III, Il, l2 reaches fully closed position beiore the pin 2l has reached the line AA, and the member I2 is between the contact jaws i3, I4 before the rod tip Il reaches the buttons IB, 31. The springs Il, I9 bias outwardly the buttons 36, 31 and thus as the switch tip I2 enters between the jaws I3, Il there is a wiping action between the buttons and the jaws. The members are so proportioned that the buttons are thereby pressed inwardly. 'I'hen as the tapered tip 35 enters between the buttons and spreads them outwardly a heavy pressure contact is established between the contact jaws, the buttons, and the rod I3. When all members are in the fully open position, the latch 28 is engaged with the projection 29 on arm 28, and so as the arm 25 moves from the open to the closed position, the arm 26 moves similarly, thereby stressing the spring 21 by which the arm 26 is continually biased towards the iully open position.

The nal closing o! the metallic circuit occurs between the tip 36 and the buttons with their springs, and as the switch is opened, the first separation in the metallic circuit is between the tip I! and the buttons 36, 31 with their springs I8, 28. In so opening, the rod 33 is snapped instantly to its fully open position and this draws the arc backwards into the tube, thereby extinguishing it in the well known expulsion-tube manner. This spring-actuated motion o! the rod elongates the arc within the tube instantly, and so creates momentarily a high pressure oi the gases within the tube. This gives an arcquenching effect similar to that of the expulsion tube fuse. The momentary high gas pressure built up by proper action, in turn tends to increase still more the speed of motion oi the rod I5, which is finally stopped by the cushion stop Il. A slower motion of the rod, however, would allow time for the gases to escape without building up the desired high pressure, and so the arc would not be broken but would seriously burn the apparatus. We have found that the rapid sweeping action of the gases which are being expelled from the swing end of the tube tends to transfer current flow from the springs or buttons inside the tube to the edge I0 of the large terminal casting, where the motion of the gases is less rapid. 'Ihis reduces the burning on the springs and buttons.

The ratchet has several teeth, any one of which will trip the latch 28 as the switch starts to open. Therefore even it the switch has not been fully closed before its opening motion starts, it will nevertheless release the arm 26 for instantaneous spring-actuated operation of the rod 32.

Without departing from the purpose and spirit o! this invention, one familiar with the art may readily make modiilcations oi the structure here described, which is to be considered as explana tory` not limitary.

We claim:

i. In an electric switch, a stationary contact and an arm movable into and out oi engagement with said contact, the said arm including In insulating tube and a conductor within the tube movable to close or to open .the circuit therethrough, a stud member supported by the said arm transversely to the said tube and making contact on the inside with the said conductor and making contact on the outside with the said stationary contact.

2. In an electric switch, an insulated contact, a switch arm movable into and out o! engagement with the said contact, the said switch arm including an insulating tube, a rigid conductor within the tube, spring means to bias the con ductor longitudinally oi the tube towards its open circuit position; together with closing means operable to move the switch arm towards closed circuit position and simultaneously to move the said rigid conductor longitudinally oi the tube towards its closed circuit position within the tube and thereby to stress the said spring means.

3. In an electric switch, an insulated contact, a switch arm movable into and out of engagement with the said contact, an operating member connected with the switch arm to open or to close the switch, the said switch arm including a base upon which are supported spring means and holding means, a straight expulsion tube mounted upon the said base and rigid with it, a straight stil! conducting member within the tube to conduct current therethrough. the said spring means biasing the said conducting member longitudinally of the tube to open the circuit therein, the said holding means restraining the said spring means; together with releasing means operable by the said operating member to initiate the release the said holding means before the switch arm moves to open the switch.

4. In an electric switch, an insulated contact, a switch arm movable into and out of engagement with the said contact, an operating member connected with the switch arm to open or to close the switch, the said switch arm including a base upon which are supported spring means and holding means, a straight expulsion tube mount ed upon the said base and rigid with it, a straight stiil conducting member within the tube to conduct current therethrough, the said spring means -biasing the said conducting member longitudinally of the tube to open the circuit therein when the switch is being opened, the said spring means retaining the said conducting member in its open circuit position relative to the tube until the said switch arm has reached its fully open position.

5. In an electric switch, an insulated contact, a switch arm movable into and out' of engagement with the said contact, the said switch arm including an expulsion tube, an operating chamber rigid with the tube and movable therewith, a rigid conductor movable within the tube to complete the circuit and w carry current therethrough and which is retractible away from the contact-making end of the tube and inw the operating chamber to open the circuit within the tube; together with spring means within the operating chamber operable to cause instantaneous motion of the said rigid conductor when the switch is being opened, and to retain the said conductor in fully open position relative to the tube until the switch arm reaches fully open position.

6. In an electric switch, arc suppressing means comprising an expulsion tube, a conductor therein movable to close or tol open the circuit therethrough, spring means to bias the conductor to open circuit position, holding means to restrain the said spring means, a swing arm operable through the said holding means to move the said conductor from its open circuit position withinv the tube to its closed circuit position and simultaneously to stress the said spring means and also operable by a reverse motion to release the said holding means.

'1. In an electric switch, an insulated contact, a switch arm movable into and out of engagement withthe said contact, the said switch arm including a straight expulsion tube, a straight conductor within the tube movable to open or to close the circuit therethrough, spring means to bias the said straight conductor to open circuit position, holding means to restrain the said spring means; together with a pivot bodily movable with the switch arm, an operating arm mounted on the said pivot and movable to move the said straight conductor into closedl circuit position, and also movable to release the said holding means as the switch is being opened.

8. In an electric switch, an insulated contact, an expulsion tube switch arm movable into and out of engagement with said contact, a rigid conductor within the tube and movable longitudinally thereof to open or to close the circuit therethrough, a latch for normalb' holding the conductor in closed circuit position,a spring for moving the conductor instantly to open circuit position when the latch is released, an operating chamber rigid with the tube and movable therewith, an operating arm pivotally mounted in the chamber and movable angularly to release the latch as the switch is being opened.

9. In an electric switch. an insulated contact, an expulsion tube switch arm movable into and out of engagement with said contact, a rigid conductor within the tube and movable longitudinally thereof to open or to close the circuit therethrough, a latch for normally holding the conductor in closed circuit position, a spring for moving the conductor instantly to open circuit position when the latch is released, an operating chamber rigid with the tube and movable therewith, an operating arm pivotally mounted in the chamber and movable angularly to release the latch, a crank arm connected. with the operating arm and movable to impart angular movement thereto and to move the switch arm into and out of engagement with the contact, and movable beyond center with respect to the operating arm when the tube is engaged with the contact, whereby upon initial movement of the crank arm from closed circuit position, the operating arm is moved about its pivot and the latch is released to open the circuit within the tube before the tube switch arm is disengaged from the contact.

10. In an electric switch, two stationaryinsulator umts, a rotatable insulator unit adjacent to the stationary insulator units, a nxed contact on one of the stationary units. an expulsion tube type switch arm pivotally mounted on the other stationary unit to swing into and out of engagement with the fixed contact, a rigid conductor within the tube and movable longitudinally thereof to open or to close the circuit therethrough, a latch movable with the switch arm for normally holding the conductor in 'closed circuit position, a spring for moving the conductor instantly to open circuitl position when the latch is released, an operating arm disposedA to release the latch from closed circuit position to allow movement of ,the conductor from closed circuit to open circuit position, and a crank arm on the rotatable insulator and connected to the operating arm, and movable beyond center with respect to the operating arm when swinging the connector into engagement with the xed contact, thereby to provide additional angular motion for operating the said latch.

11. In combination, in an electric switch, a switch arm movable to open or to close the switch; together with arc-suppressive means, coordinated with the said switch arm and which include an expulsion tube, a rigid conductor within the tube movable to open or to close the circuit therethrough, spring means to bias the said conductor towards open circuit position, holding means to restrain the said spring means, and releasing means operable to release the said holding means when switch opening motion begins from any one of a multiplicity of different positions of the switch arm.

l2. In combination, in an electric switch, a switch arm movable to open or to close the switch; together with arc-suppressive means, coordinated with the said switch arm and which include an expulsion tube, a rigid conductor within the tube movable to open or to close the circuit therethrough, spring means to bias the said conductor towards open circuit position, latch meansto restrain the said spring means, and releasing means to release the said latch means as the switch starts to open, the said releasing means including spaced notches operable to release the said latch means at correspondingly spaced positions of the said conductor.

13. In a circuit breaker, a straight tube of insulating material, an operating chamber adiacent to one end of the tube and rigidly connected to the tube, a straight rigid conductor operable within the tube to close the circuit and to carry current therethrough, holding means to keep the circuit closed, an arm pivotally mounted within the said chamber and connected with the said rigid conductor to move it at least partially out of the tube and into the chamber to open theYV circuitwithin the tube, together with spring opening means to move the arm andthe lsaid rigid conductor instantly from closed to open position when the said holding means are released.

OLAN RICHARDSON. WILLIAM A. GUSSOW. JOHN R. CALDWELL. 

